Mesoscale Variability of the Ocean in the Northern Part of the Weddell Sea

Oceanology - Results of a mesoscale survey in the Powell Basin in the northern part of the Weddell Sea are analyzed. The survey included 24 CTD casts (6 × 4) with an interval of six nautical...     

Genesis of fragmental carbonate rocks in the Mesozoic and Tertiary of Mallorca,Spain

Fragmental carbonate rocks are common in the Mesozoic and Tertiary succession of Mallorca, in the western Mediterranean. On the Formentor peninsula at the northeastern end of the Sierra Norte, two phases of fragmentation post-date Liassic platform carbonate and its subsequent reworking, and predate deposition of marine Burdigalian sediments. Phase 1 fragmentation resulted in brecciated rocks with angular fragments often little displaced, cemented by coarse calcite. Brecciated rock passes into veined or unbrecciated rock over short distances. These breccias are interpreted as the products of collapse during solution of an evaporite after uplift during the early Tertiary. Phase 2 fragmentation is related to the unconformity with Miocene sediments and is interpreted as a product of karstic processes operating prior to subsidence and deposition of Miocene marine conglomerates. Multiple brecciation is common, yielding complex fragmental rocks, but permitting a relative dating of the two phases and other depositional and structural events.     

Photographic photometry for stellar statistics with Tautenburg Schmidt telescope

Photometric properties of deep Tautenburg Schmidt plates in the UBV system over the whole field and over a wide range of stellar magnitudes are discussed. Different reduction models based on the calibration curve alone and with additional terms containing colour and plate coordinates are considered. With the filter-emulsion combinations used the Johnson UBV system can be reproduced quite well by the Tautenburg telescope. The accuracy of photometric data can be improved if geometrical terms are taken into account. For deep plates with a significant effect of background nebulosity a supplementary term is to be included in the reduction model. The polynomial coefficients vary in dependence on spectral bands and individual properties of each plate.     

Mini-inflation prior to the cosmic confinement transition?

The onset of the confinement transition in the early universe is studied within the Friedmann model. Exploiting a bag model equation of state for the deconfined matter, which is generalized to include also metastable states, the possibility of a mini-inflationary epoch is demonstrated. A criterion of metastability is derived to estimate parameters of this mini-inflation.     

Die Entdeckung eines neuen Asteroiden (1988BJ) vom “Hungaria”-Typ

During an observational program of asteroids at the observatory of Haute Provence (France) an asteroid of 17^th magnitude was discovered on 22^nd January 1988 (Elst 1988). Further observations at the European Southern Observatory (ESO) and a preliminary determination of an orbit revealed that it belongs to the “Hungaria” family.     

The Humphrey Head Borehole: Evidence for Carboniferous vulcanicity and Permian dolomitization in the southern Lake District

In south Cumbria, Permo-Triassic breccias and conglomerates (‘brockram’) are exposed only at Rougholme Point on the Cartmel peninsula. In 1973 the Institute of Geological Sciences Humphrey Head borehole penetrated 257 m of brockram before entering probable Upper Carboniferous sediments. The brockram consists of pebbles of carbonate, chert and basalt in a matrix of haematite-stained quartz sand. Carbonate and chert fragments were derived from the upper part of the Carboniferous Limestone sequence exposed today nearby. Basalt clasts were derived from lavas, which appear to have cooled in a subaqueous environment, at least in part. They were locally derived and are the only certain evidence for Carboniferous volcanic activity in south Cumbria. As volcanic fragments increase in abundance towards the base of the borehole they must have been derived from the top of the succession being eroded and are probably of Brigantian age. Carbonate fragments were dolomitized soon after incorporation in the brockram, probably by saline fluids derived from the evaporative Zechstein Sea. The dolomitization was incomplete, leaving remnant limestone cores to clasts which were subsequently dissolved. The resultant vugs were infilled by dolomite, calcite and gypsum cements, which have been partially weathered from outcropping brockram, leaving hollow pebbles.     

Adaptive Transitions: The Long‐Term Perspective on Humans in Changing Coastal Settings

Adaptation is a key concept in long‐term human adjustments to climate change. Despite the centrality of human decisions and actions in adaptation, much of the climate change literature is thin on humanities and social science which are the primary approaches for understanding human activity. This situation is particularly pronounced in Louisiana's discussions about its disappearing coast line where research has concentrated in understanding biophysical processes and solutions prioritize short‐term adaptations. This paper reviews the relationship of adaptation and long‐term transitions in the global change discussion and traces how disjointed adaptations in coastal Louisiana have contributed to a perilous environmental situation there. It proposes a shift from discrete adaptations to efforts that incorporate interrelated biophysical and human adaptations that can sustain long‐term transitions.     

Strain analysis of a seismically imaged mass‐transport complex,offshore Uruguay

Strain style, magnitude and distribution within mass‐transport complexes (MTCs) are important for understanding the process evolution of submarine mass flows and for estimating their runout distances. Structural restoration and quantification of strain in gravitationally driven passive margins have been shown to approximately balance between updip extensional and downdip contractional domains; such an exercise has not yet been attempted for MTCs. We here interpret and structurally restore a shallowly buried (c. 1,500 mbsf) and well‐imaged MTC, offshore Uruguay using a high‐resolution (12.5 m vertical and 15 × 12.5 m horizontal resolution) three‐dimensional seismic‐reflection survey. This allows us to characterise and quantify vertical and lateral strain distribution within the deposit. Detailed seismic mapping and attribute analysis shows that the MTC is characterised by a complicated array of kinematic indicators, which vary spatially in style and concentration. Seismic‐attribute extractions reveal several previously undocumented fabrics preserved in the MTC, including internal shearing in the form of sub‐orthogonal shear zones, and fold‐thrust systems within the basal shear zone beneath rafted‐blocks. These features suggest multiple transport directions and phases of flow during emplacement. The MTC is characterised by a broadly tripartite strain distribution, with extensional (e.g. normal faults), translational and contractional (e.g. folds and thrusts) domains, along with a radial frontally emergent zone. We also show how strain is preferentially concentrated around intra‐MTC rafted‐blocks due to their kinematic interactions with the underlying basal shear zone. Overall, and even when volume loss within the frontally emergent zone is included, a strain difference between extension (1.6–1.9 km) and contraction (6.7–7.3 km) is calculated. We attribute this to a combination of distributed, sub‐seismic, ‘cryptic’ strain, likely related to de‐watering, grain‐scale deformation and related changes in bulk sediment volume. This work has implications for assessing MTCs strain distribution and provides a practical approach for evaluating structural interpretations within such deposits.     

Network analysis to inform invasive species spread among lakes

Often facilitated by human-mediated pathways,aquatic invasive species are a threat to the health and biodiversity of global ecosystems.We present a novel approach incorporating survey data of watercraft movement in a social network analysis to reconstruct potential pathways of aquatic invasive species spread between lakes.As an example,we use the green alga Nitellopsis obtusa,also known as starry stonewort,an aquatic invasive species affecting the Great Lakes region in the United States and Canada.The movement of algal fragments via human-mediated pathways(i.e.,watercraft)has been hypothesized as the primary driver of starry stonewort invasion.We used survey data collected at boat ramps during the 2013 and 2014 openwater seasons to describe the flow of watercraft from Lake Koronis,where N.obtusa was first detected in Minnesota,to other lakes in the state.Our results suggest that the risk of N.obtusa expansion is not highly constrained by geographic proximity and management efforts should consider highly connected lakes.Estimating human movement via network analysis may help to explain past and future routes of aquatic invasive species infestation between lakes and can improve evidence-based prevention and control efforts.